Buggy code:
public class WampClient { private static final Logger logger = Logger . getLogger ( WampClient . class . getName ( ) ) ; private String urls ; private String password ; private String helloRealm ; private WampEncoding preferredEncoding ; private WampEncoding encoding ; private WampApplication wampApp ; private WampSocket clientSocket ; private int taskCount ; private ConcurrentHashMap < Long , String > rpcRegistrationsById ; private ConcurrentHashMap < String , Long > rpcRegistrationsByURI ; private ConcurrentHashMap < Long , WampMethod > rpcHandlers ; private ConcurrentHashMap < Long , String > topicPatternsBySubscriptionId ; private ConcurrentHashMap < Long , WampList > pendingRequests ; private ConcurrentHashMap < Long , WampCallController > pendingInvocations ; public WampClient ( String urls ) throws Exception { } public WampApplication getWampApplication ( ) { } public WampSocket getWampSocket ( ) { } public boolean isOpen ( ) { <START_BUG> return clientSocket . isOpen ( ) ; <END_BUG> } @ SuppressWarnings ( "unchecked" ) private Deferred < Long , WampException , Long > getDeferredLong ( WampList request ) { } @ SuppressWarnings ( "unchecked" ) private Deferred < WampResult , WampException , WampResult > getDeferredWampResult ( WampList request ) { } private List < String > getPreferredSubprotocolOrder ( ) { } public void setPreferredWampEncoding ( WampEncoding preferredEncoding ) { } public void connect ( ) throws Exception { } public void goodbye ( String reason ) { } public void hello ( String realm , String user , String password , boolean digestPasswordMD5 ) throws Exception { } public void hello ( String realm , WampDict authDetails ) throws Exception { } public Promise < Long , WampException , Long > publish ( String topic , WampList payload , WampDict payloadKw , WampDict options ) throws Exception { } public Promise < WampResult , WampException , WampResult > call ( String procedureUri , WampList args , WampDict argsKw , WampCallOptions options ) throws Exception { } public void cancelCall ( Long callID , WampDict options ) throws Exception { } private void processSubscribedAnnotations ( ) throws Exception { } private void processRegisteredAnnotations ( ) throws Exception { } public Promise < Long , WampException , Long > registerRPC ( WampDict options , String procedureURI , WampMethod implementation ) throws Exception { } public Promise < Long , WampException , Long > unregisterRPC ( String procedureURI ) throws Exception { } protected Promise < Long , WampException , Long > unregisterRPC ( Long registrationId ) throws Exception { } private String getTopicPattern ( String topicPattern , WampSubscriptionOptions options ) { } public Promise < Long , WampException , Long > subscribe ( String topicURI , WampSubscriptionOptions options ) throws Exception { } public Promise < Long , WampException , Long > unsubscribe ( Long subscriptionId ) throws Exception { } private void createPendingMessage ( Long requestId , WampList requestData ) { } private void removePendingMessage ( Long requestId ) { } public void waitResponses ( ) throws Exception { } public String getTopicFromEventData ( Long subscriptionId , WampDict details ) { } public void close ( ) throws Exception { } }

Fix:
return ( ( clientSocket ) != null ) && ( clientSocket . isOpen ( ) ) ;